Method and apparatus for covering a scale for the handle of a pocket knife



P. RICHARTZ' 9 9 METHOD AND APPARATUS FOR COVERING A SCALE OF A POCKETKNIFE FOR THE HANDLE 4 Sheets-Sheet 1 Filed Sept. 22, 1945 I-nvenzahPaul Riclarl:

Ga. 26 1948. P. RICHARTZ 2,452,149

/ METHOD AND APPARATUS FOR' COVERING A SCALE FOR THE HANDLE OF A POCKETKNIFE a 4 Sheets-Sheet 2 Q Filed Sept. 22, 1945 fi;/'%Z1" 12011221 22L'cZLa Get. 26, 194

Filed Sept. 22, 1945 METHOD AND FOR TH P. RICHARTZ APPARATUS FORCOVERING A SCALE E HANDLE OF A POCKET 'KNIFE 4 sheets-sheet 5(Willi-\Wlllll/I/I/I/I/III P 2112 Hickgrl:

Filed Sept. 22, 1945 P. RICHARTZ 0D AND APPARATUS FOR COVERI FOR THEHANDLE OF A POCKET me A SCALE KNIFE 4 Sheets-Sheet 4 Patented a. 2c,1948? I UNITED STAT METHOD AND A SCALE FOR KNIFE APPARATUS THE HANDLE OFA POCKET FOR COVERING This invention relates to an improved method andapparatus for covering a scale for the handle of a pocket knife with asheet of deformable material, such as thermoplastic sheet and has for anobject to provide means for mechanically applying the sheet materialwithout harmful effects to it.

It has already been proposed to apply a sheet of thermoplastic materialto a knife scale by employing a sheet of sufficient size as to providemarginal edges which may be folded over the edges of the scale, and byapplying heat more intensely to the folds than to the remainder of thematerial, and by engaging said marginal edges by members which duringtheir inward movement over the scale, are arranged to compress thethermoplastic material between them and the edges of the scale so as tosubject the material to tension. It is found in practice that the foldsthus formed are liable to be weakened by the combined heating andstretching, and the present invention has for an object to avoid thatdefect.

According to this invention, a method for cov ering a scale for a pocketknife with deformable sheet material consists in placing the sheetmaterial over the cavity in a mould shaped to the contour of the scale,placing the scale on the sheet material over the cavity, forcing thescale and sheet material into the cavity, which material is sodimensioned that its marginal edges project away from the mould and fromthe edges of the scale, applying lateral forces to said marginal edgesover an area spaced away from the edges of the scale by an amountgreater than the thickness of the material, whereby the material is bentover the edge without excessive stretching. If necessary, the abovesteps are followed by applying pressure to said bent-over marginalportions in a direction towards the face of the scale. This latter stepis'particularly suitable when a hollow-pressed metal scale is employed,and wherein the marginal edges of the material are required to liewholly within the hollow of the scale.

In the case where a thermoplastic sheet is employed, it is heatedsubstantially uniformly over its area so as to render it permanentlydeformable, so that when said marginal edges are folded over the scale,they reman permanently set.

. In the case where the metal scale is provided ment of the shutters,the

4 Claims. (Cl. 1819) with upraised bolsters, the deformable material isso dimensioned that its end marginal edges are located adjacent theupraised bolsters.

The invention is also applicable to covering a scale with deformablematerial around an upstanding ornamentation such as a shield, in whichcase the cavity in themould is provided with a recess having sharp edgesconforming to the shape of the upraised ornamentation, so that when thescale and the sheet material are forced into the cavity, the upraisedportion enters into a recess and the sharp edges cut through thematerial, whereby the cut portion may be removed to expose theornamentation.

An apparatus for carrying out the above process may comprise a press, amould having a cavity shaped to the contour of the scale, a reciprocablepress tool operated by said press and adapted to force said sheetmaterial backed by the scale into the mould, which material is sodimensioned that itsmarginal edges project from the mould, laterallyslidable shutters associated with said mould and adapted to engage saidmarginal edges at a distance away from the edges of the scale by anamount greater than the thickness of the material, means for applyingreciprocable movement to said shutters. In the case where athermoplastic sheet is employed, means are provided for heating saidmould. Preferably, means are provided for locating the sheet materialbacked by the scale over the cavity in the mould.

In'order to prevent the sheet material from being compressed andstretched during the movedepression in the mould may either be arrangedso that the edges of the scale lie substantially flush with the face ofthe mould and the shutters are guided so as to be spaced away from thetop of the mould by an amount greater than the thickness of material, orthe depression in the mould may be such that the edges of the scale liebeneath the top face of the mould by an amount greater than the thickness of material, and the shutters are arranged to slide over the topface of the mould.

Movement may be imparted to the shutters by a flexible element attachedto each of them and passing over a guide pulley and by a pedal leverattached to the ends of the flexible element, resillent means beingprovided to resist the movement applied to the shutters by the pedal.

The reciprocable press tool may also be arranged to be operated by afoot pedal. Thus, when the first said pedal is depressed to open theshutters by one foot, the other pedal is operated by the other foot.

The means for heating the mould may oomprise a base plate on which themould and sliding shutters are mounted, to the back of which base platethere is secured an electric heating element. By these means, the wholeof the mould and the'shutters are heated to a uniform temperature,

The following is a description of one form of apparatus, and twoalternative constructions of mould for forming a knife scale accordingto this.

invention, reference being made to the accompanying drawings, in whichFigure l is a side elevation of the apparatus;

Figure 2 is a plan view on an enlarged scaleof one form of mould andassociated shutters;

Figure 3 is a section on the line 3-3 of Figure 2;

Figure 4 is an enlarged view of a part of Figure- 3. showing the initialposition of the sheet Celluloid covering and hollow metal. scale inrelation to the mould;

Figure 5 to. 7 show the covering and scale after successive operationscarried out by the apparatus;

Figure 8 is a similar view of Figure 2, showing an alternative form ofmould;

Figure 9 is a cross-section on the line 9-9 of Figure 8;

Figure 10 is a crossesection on the line l0l0 of Figure 8;

Figure 11 is a. mould block; and

Figure. 12 is a. section through a hollow pressed metal scale having anornamentation and which iscoyered by means of the mould block of Figure11.

Referring to the construction shown in Figure 2, the mould comprises abase plate 10 on which are secured end blocks II and 12 by setscrews [3.The blocks are provided with vertically-extending grooves l4 and I5facing one another, and the contours of which grooves correspond withthe contours of the bolster of the knife. A main mould block I6 isdisposed between, the end blocks H and I2 and is provided with'adepression I! in the upper face thereof corresponding in shape to theshape of the knife scale. The main mould block [6 is provided with endpieces I 8 and [9 which engage the grooves nd blocks, therebymaintaining the main block in position, but so that it can be readilyremovable. In the case where the bolster end of the metal knife scale isprovided with a lug by which it is attached to the skeleton of theknife, the block I I may be provided with a recess 28 extending'partlydown the depthof the block for initially accommodating thelug, but whichserves to bend the lug during the operation of the apparatus, ashereinafter described; Mounted in slideways 2| on either side of: themain'mould block. are fiat shutters 22, which slideways are so, locatedthat the shutters may move over the top of the mainmould block I6 andmeet one another, as shown in Figure 3. The shutters are urged towardsone another by means of tension springs 23 secured at one end 24. to theshutters, and at the other end 25, to

plan view of an alternative the. base plate 40. The shutters: may bemoved spacing members 632 at its apart by chains 26 secured to them at21 and passing over sprocket wheels 28 mounted in suitable recesses 25)at the sides of the base plate. The base plate is heated beneath themain mould block it by an electric heating element 38 attached to theunderside of the base plate. The degree of heating may be controlled bya switch 3! which connects in varying lengths of the resistance to theelectric supply,

An alternative form of mould is shown in Figures 8 to 10. In thisarrangement, the mould block 16 is mounted to slide vertically in 2.casing part 61 secured to the base plate l0. As in the. previousconstruction,v shutters 22 are arranged to slide in slideways 2i and areoperated against the action of springs by means of chains 26. In. th sinstance, however, the top face of the casin Part 6! is recessed at 54to provide channels in which the shutters may slide, either by formingthe recesses in the material of the casing .part,.or as shown in Figure10, providing ends, and the slides 2| are prevented from rising in theserecesses by a. cover plate 55 secured over the top of the casing part 6|by studs 56. The cover plate is provided. with an aperture having edges:5'! and 58.so shaped and disposed as toregister the $heet Celluloidcorrectly over the recess in. the mould. It is also provided with otheredges 59 and. 60 shaped to correspond with the bolster ends of the scaleand guide it correctly into engagement with the depression I 1 in themould block l6, except, in. this instance, the shutters. 22 slide overthe top face of the mould block 15 within, the aforesaid'casing, Thedepth oi the portion it of the mould part is suffieiently great thatwhen the metal. scale and Celluloid sheet havev been pressed into it,the edges. of the metal scale lie below the top of-the mouldblock by an.amount greater than the thickness of the Cellue loid sheet. Thus, whenthe Celluloid Sheet. is bent over the edges of the metal scale by theslides 22, it is not subjected to compression or excessive stretch, asreferred. to above.

It is usual for the covering of the scale to. lie flush with or slightlybelow the surface of the bolstera, andfor this purpose, the scale is initially hollow-pressed,toprovide a countersunk portion between thebolsters which are left up: standing, and. the edges of the scale arerecessed between the bohters by an amount equal to or greater than thethickness. of the Celluloid sheets. In order that the mould block 16 maybe readily removed from. the casing part 61., the, bottom wall as of thecasing provid d with two holes at through which extend two. pins 55.actuated by the forked end of a lever arm 46 having. a manipulatinghandle .47.

As, will be seen from Figure. 1, the base plate Ill and the. mould on itarev secured to the base 32 of a foot-operated press 3 3.mounted on apodestal 34. The press. is provided with afsquaresection plunger 35.reciprocably mounted in. bear-- ings 36 at the ends. of cantilever arms31., The plunger is provided. with a slot. 38 in which located the endof a lever-.arm..39., The. leverarm is pivoted at, .40; in the main,upright portion of the press, and is provided with. a double, crankedarm 4| extending downwardly, andthen forwardly, where. it is providedwith a. pedal extremity 42. The. two chains 26 extend downwardly from.the sprocket wheel 28' and are. at. tached attheir lower ends toafootelever 4 3.-piv. oted at .44 to. the bee of the pedestal, andpro-.- vicled, with a. pedal. 45. Thus, by depressing the pedal 45 theaforesaid shutters 22 are drawn apart against the action of the springs23. The lower end of the plunger 35 has secured to it a press tool 48,the end of which is shaped to correspond with the internal contour ofthe hollow-pressed metal scale.

The operation of applying the Celluloid sheet covering to the metalscale is now described with reference to Figures 4 to 7, which embody amould and shutters as described with reference to Figures 2 and 3. Thetemperature of the base plate Ht is so adjusted to a degree which willrender the Celluloid sheet pliable. The foot pedal 45 is depressed so asto separate the shutters 22, and, as seen in Figure 4, the Celluloidsheet 49 is first laid over the main mould block it, which sheet is sodimensioned as to extend between the bolster ends of the sheet metalscale 50 and is sufficiently wide as to permit it eventually to be bentaround the curved contour of the scale, and then inwardly over the edgesof the scale, as shown in Figure '7. The Celluloid sheet while in theposition shown in Figure 4 is raised to substantially the sametemperature over the whole of its area so as to render it deformable.

As indicated earlier in the specification, the bolster ends of the scalemay be provided with lugs 5|, and the metal scales are inserted betweenthe blocks II and I2, with the lugs in the slots 20. The slots are ofsufficient depth to permit the scale to rest on the Celluloid sheet 49,as shown in Figure 4.

The next operation consists in forcing the hollow metal scale andCelluloid covering into the mould part l6 by means of the press tool 14which is forced downwardly by pressure on the foot-pedal 42 by one foot,while the other foot maintains the other pedal 45 depressed. Themarginal edges 52 of the Celluloid sheet are caused by this operation toextend upwardly, and the parts remain in this position during theoperation of withdrawing the press tool 48. The next operation, which isshown in Figure 6, consists in moving the shutters comparatively rapidlyinwardly and outwardly. This is effected by momentarily releasing thepressure on the footpedal 45. The above steps follow one another in suchquick succession that although the marginal edges momentarily leave theface of the mould they remain at substantially the same temperature asthe remainder of the sheet which is sufiicient to render the sheetdeformable.

It will be noted that the shutters 22 are so disposed in their slides 2|as to leave a gap 52 of greater width than the thickness of theCelluloid sheet between the shutters and the mould part It and the edgesof the scale. The sheet is thus bent over the edges of thehollow-pressed metal scale 50 by a simple bending movement, withoutsubmitting it to any excessive stretching action which might otherwisefracture it at the bend. As already indicated, the Celluloid sheet hasbeen rendered pliable over its whole area, including the region of theedges of the metal scale, and the efiect of this folding operation ispermanently to distort the material at the bend, so that when theshutters are removed, it remains substantially in the same condition asthat shown in Figure 6.

In order that the marginal portions 52 may be made to lie flush againstthe inside of the hollow metal scale, the press tool 48 is againlowered, as shown in Figure '7, and after withdrawal thereof, theoperation is complete.

The hollow-pressed metal scale may also be embossed to provide anupstandingornamentae tion, such as a shield 55, at a location betweenthe bolsters and the mould may initially be pro vided with a recess 56having aisharp cutting edge shaped to register with the upstandingornamentation, so that afterthesheetscale has been subjected to pressurein themould, theorna-r mentation lies flush with the surface thereof.Iclaim: .xI-Lw.

1. An apparatus, for coveringuga scaleufor aa pocket knife withdeformable-sheet-materiaLcomprising a press, a mould having acayitysshaped to. fit said scale andso that the edges of the scale liebeneath the face of the mould by an amount greater than the thickness ofthe sheet material, a reciprocable press tool vertically operated bysaid press and adapted to force said sheet material backed by the scaleinto the mould, said press tool having a width equal to the width of thescale to contact the entire width of the scale during the pressingoperation and said material having its marginal edges projecting fromthe mould, laterally slidable shutters movable horizontally andassociated with said mould to engage said marginal edges, means forapplying reciprocable movement to said shutters so that they slide onthe surface of said mould into engagement with the marginal edges of thematerial, and means for applying reciprocable movement to said shutters,and means for heating said mould.

2. An apparatus for covering a scale for a pocket knife with deformablesheet material, comprising a press, a mould having a cavity shaped tothe contour of the scale, a reciprocable press tool, a foot pedalconnected to operate said press tool and to force said sheet materialbacked by the scale into the mould, said material having its marginaledges projecting from the mould, laterally slidable shutters, slidewaysfor said shutters adapted to guide them into engagement with saidmarginal edges, a flexible element attached to each shutter and passingover a guide pulley, a foot pedal lever attached to the ends of theflexible elements, resilient means resisting the movement applied to theshutters by the pedal and means for heating said mould.

3. A method of covering a scale for a pocket knife with deformable sheetmaterial which consists in placing the sheet material over the cavity ina'mould shaped to the contour of the scale, placing the scale on thesheet material over the cavity, applying vertical pressure over thegreater part of the area of the scale so as to force it and the sheetmaterial into the cavity, said material being so dimensioned that itsmarginal edges project away from the outer face of the mould and fromthe edges of the scale, applying horizontal forces to said marginaledges over an area spaced away from the edges of the scale by an amountgreater than the thickness of the material to bend the material over theedge of the scale without excessive stretching, and applying verticalpressure to said bent-over marginal portion in a direction towards thebase of the scale to force them arginal portion against the insidecavity of the scale.

4. A method of covering a scale for a pocket knife with deformable sheetmaterial which consists in placing the sheet material over the cavity ina mould shaped to the contour of the scale, placing the scale on thesheet material over the cavity, vertically moving a press tool on thescale and sheet material to force them into the cavity and thereaftermoving the press tool out of the cavity, said material being sodimensioned that 7 its marginal :edges profiept away from the 'mmld andlrqm thfe edges of the scale, applying lateral fqrges-td-said marginaledges by horizontally movable shutters eover an' area spaced away fromREFERENCES CITED The following references are of record 111 the file ofthis patent:

UNITED STATES PATENTS Number Name Date Miranda et a1 June 2, 1942

